This paper presents an acoustic-based microfluidic platform for active manipulation and separation of micro-particles. An acoustic radiation force (ARF) is generated as a driving force on a piezoelectric Lithium Niobate (LiNbO3) wafer using patterned interdigitated transducer (IDT) electrodes on its surface to manipulate micro-particles precisely. On top of the wafer, a polydimethylsiloxane (PDMS) channel is bonded to allow the flow of the micro-particles. The supplied electric current to IDTs produces a vibration motion on the surface of the wafer. This vibratory motion has a distinct effect on different micro-particles depending on their size, density, and compressibility. In this paper, a separation of 6 μm from 14 μm diameter Polystyrene (PS) particles suspended in deionized water at a high flow rate of 200 μl/hr is demonstrated.
Liposomes are bilayer lipid membranes that can encapsulate drugs in the internal hydrophobic part of the hydrophilic bilayer. In targeted drug delivery, liposomes are used to deliver and target certain diseases to avoid any drug side effects. Instead of chemotherapy, treating breast cancer can be done using targeted drug delivery by Estrone conjugated liposomes that will reach the tumor site due to the receptors found on the membrane and nucleus of the cancer cells. Estrone liposomes can be synthesized using conventional techniques but have limitations. Microfluidics offers advantages over conventional techniques such as lower liposome size, better uniformity and reproducibility. Microfluidic hydrodynamic focusing (MHF) will be investigated for synthesis of estrone liposomes. In MHF, a stream of solvents containing the lipids is sandwiched between two buffer streams inside a microchannel. The small size scale involved enables rapid solvent exchange and initiates self-assembly of the lipids to form the required liposomes.
This work investigates the ability to sense glucose concentration in a water solution using a Reduced Graphene Oxide (rGO) based memristor. Planar memristors were fabricated using standard photolithography microfabrication techniques with different electrodes. The memristor sensor demonstrated the ability to detect different levels of D-glucose concentration represented as different Off/On resistance ratios of the device. This work is the first to establish a response of rGO-based memristor to glucose concentration, it opens the way to low-cost non-enzymatic screening for glucose level.
This paper discusses a possible design of a microfluidic contact lens that is highly sensitive to intraocular pressure (IOP). Normal eye pressure ranges between 10-21 mmHg, and eye pressure of greater than 21 mm Hg is directly related to glaucoma. The contact lens includes twelve capillary burst valves (CBV) designed with different widths, each corresponds to a specific IOP. The increase of IOP is represented by a noticeable fluid movement in the designed CBV's. The first designed CBV will burst when the IOP is larger than 10 mmHg, while the last one will burst when the IOP is larger than 37.5 mmHg. The uncertainty of the measured IOP is 2.5 mmHg, which is the difference between two adjacent burst pressures (BP).
In this study, novel ultrafiltration membranes were prepared via blending cobalt-substituted aluminophosphate (CoAPO-5) plate-like crystal aggregates into polyethersulfone membranes to enhance membrane selectivity for the separation of bovine serum albumin from water. The proposed rejection mechanism is based on size exclusion, formation of hydration layer, and electrostatic interactions exhibited by the composite membranes upon doping with CoAPO-5.
Leonardo da Vinci commented, "water is the driving force of all nature". Freshwater scarcity is increasingly perceived as a global systemic risk. Recently, atmospheric water harvesting (AWH) becomes a promising strategy for decentralized water production. This work aims to design and prepare novel hybrid sorbents to be used for water vapor harvesting under various weather conditions. Synthesis of aluminophosphate (AlPO)-based composites and characterization were carried out to test material properties, stability, and compatibility. Essential benefits are targeted from the developed composites, namely, efficient operation within broad RH% and high capacity. Also, the incorporation of AlPO particles within sodium alginate and polyacrylamide improved the thermal stability of the latter. These properties make these hybrids a promising candidate in future AWH systems.
Vast amount of dye-containing wastewaters from many industries need careful treatment. The adsorption kinetics of methyl orange (MO, an azo dye) on a waste cellulose-derived mesoporous carbon was investigated for application. Simulation results revealed that adsorption kinetics can be well simulated/predicted using the pseudo-second order (PSO) model. Single-staged and two-staged batch adsorbers were designed using experimental data with optimal adsorption times for achieving various removal efficiencies. The results are important in treatment of such wastewaters and can be used in practical design and operations.
Hydrogen is considered the simplest element in existence and one of the most abundant in the earth found as part of another substance, such as water and hydrocarbon. Though of its simple structure, it has the highest energy content of any common fuel by weight. In near future, due to its excessive energy content, it may become one of the most environmentally friendly automobile fuels. Most oil and gas reservoirs in the United Arab Emirates (UAE) are sour, enriched with a high amount of hydrogen sulfide (H2S) and sulfur species. The conversion of H2S into H2 and Sulfur is beneficial from both environmental and energy perspectives. The two-step thermochemical decomposition of H2S is considered as one of the most promising technologies for Hydrogen production. This paper investigates the chemical kinetics of the two-step Thermochemical decomposition of H2S using Nickel Sulfide.
This paper describes the modelling of external corrosion of an underground pipeline. Pitting corrosion and Stress Corrosion Cracking are two of the most common external corrosion types for buried pipeline and they usually happen when corrosion protection methods fail or deteriorate. Pitting corrosion is a localized corrosion that occurs at local sites with no coating or cathodic protection as a results of electrochemical reaction between the pipeline material and the corrosion environment. A finite element model was developed using COMSOL Multiphysics to study the effect of the stress at the corrosion defect on the corrosion growth rate.
In the efforts to combat the increase in the excess emissions of anthropogenic CO2, CCS technologies such as solid sorbents for CO2 capture have been explored. Activated carbon is considered one of the most promising adsorbents due to its many advantages, such as its good thermal stability and excellent adsorption capacity. Activated carbons prepared from date seeds agricultural biomass have already been developed and are used in many industrial applications. However, there is not much research that explored their potential for CO2 capture applications. This study reports the preparation of chemically activated Activated carbon (AC) using KOH. Different impregnation ratios and activation temperatures were studied to find the best preparation combination for high CO2 capture capacity. At the optimized impregnation ratio of 2.5:1 and activation temperature of 600 ?C, the produced AC had the highest adsorption capacity of 2.18 mmol/g and BET surface area of 1033.09 m2/g.
